GEOLOGY

Detailed explanation-1: -Extrusive, or volcanic, igneous rock is produced when magma exits and cools above (or very near) the Earth’s surface. These are the rocks that form at erupting volcanoes and oozing fissures.

Detailed explanation-2: -Igneous rocks form when magma (molten rock) cools and crystallizes, either at volcanoes on the surface of the Earth or while the melted rock is still inside the crust. All magma develops underground, in the lower crust or upper mantle, because of the intense heat there.

Detailed explanation-3: -When lava reaches the surface of the Earth through volcanoes or through great fissures the rocks that are formed from the lava cooling and hardening are called extrusive igneous rocks. Some of the more common types of extrusive igneous rocks are lava rocks, cinders, pumice, obsidian, and volcanic ash and dust.

Detailed explanation-4: -igneous rock, any of various crystalline or glassy rocks formed by the cooling and solidification of molten earth material.

Detailed explanation-5: -The magma that comes to the surface of the Earth and solidifies forms fine-grained rocks like basalt. Basalt is a dark-colored igneous rock. Granite and Basalt are widely used for the construction of roads and buildings. Extrusive igneous rocks form when lava reaches the Earth’s surface a volcano and cools quickly.